I was watching some videos and came across with one that got the moment in which a Singapore Airlines B777 skids off the runway on landing. It happened last November.
It seems that the crew performed an autoland without advising ATC and another aircraft blocked the localizer signal or something. Fortunately nobody was seriously injured.
I hope it is not a repost.

I was on a KLM 737-700 from AMS to MUC that evening after the runway reopened, but there was a big backlog of delayed and diverted flights since one of the two runways had been closed most of the day. The KL flight I was on didn't have enough fuel to hold very long so we diverted to NUE for more fuel and finally arrived MUC about 2 hours late.

Quoting redrooster3 (Reply 6):How do they get the aircraft out of there? With it's own power? Or a tow truck.

In most cases, it´s a nightmare. It requires jacks, airbags, or both. And then it is usually towed. In this case, though, the plane taxied back onto the runway on its own power without the passengers. It really depends on wether or not the gear gets stuck and how deep.

Quoting as739x (Reply 5):I've never encountered the crew having to notify ATC they were doing an Autoland. If IFR conditions persist, then a/c are to stay out of the IFR save boundary.

In my company, Low Visibility Procedures must be in force in order to conduct a Cat II/III approach. If they are not then you cannot garentee the ILS protected area is clear of obstacles/other aircraft etc. Just because its cloudy doesnt mean that LVPs are in use, certain weather minima are usually have to be breached.

Quoting IanatSTN (Reply 11):In my company, Low Visibility Procedures must be in force in order to conduct a Cat II/III approach. If they are not then you cannot garentee the ILS protected area is clear of obstacles/other aircraft etc. Just because its cloudy doesnt mean that LVPs are in use, certain weather minima are usually have to be breached.

It is the same way at my company. LVP have to be in force from the airport's side before performing any CAT II/III approach. And then, aircraft would be advised to hold short of the CAT II/III stopbars before the runway, so the sensitive area remains clear.

The GBA reported that on approach the crew decided to perform a fully automatic landing onto runway 08R when the weather conditions were below the limits that permitted the the first officer, pilot flying to do the landing.

The captain became pilot flying, the first officer became pilot monitoring. The airport was operating according to CAT I standards.

At 2 nm before touch down a regional jet began its takeoff run on runway 08R. Winds were from 130 degrees at 7 knots. When the SQ flight crossed the runway threshold, the regional jet was climbing out short of the runway end.
At the time of touchdown of the SQ flight the regional jet was climbing out past the runway end.

When the SQ flight reached 30 feet AGL, the aircraft began to roll left, landed, and the autopilot changed into roll out mode. The aircraft kept moving towards the left edge of the runway and crossed it. Rudder inputs by the PF disengaged the autopilot

The aircraft then rolled in a slight right turn over grass for about 400 meters, before it crossed the runway edge again onto the runway and crossed the runway reaching the right runway edge and exiting said runway.. The aircraft came to a stop on grass off the runway.

The GBA says the captain tried to go-around when the aircraft began to roll left. He pressed the TOGA button, but the aircraft did not respond. He then retracted the spoilers that had automatically extended. Strange, because it does not seem in the video that the spoilers ever activated.

The GBA reports the aircraft began to roll left in response to autopilot inputs to minimize the localizer deviation and reached 3.5 degrees bank angle to the left when the autopilot changed to roll out.

Very contradictory to the captain´s statements is the fact that there were no indications of the TOGA button pushed on the FDR.

So. Not my intention to second guess this crew´s landing attempt but it does not seem that there was an autopilot/ILS issue per se.

We dont know the whole story, but perhaps a rushed approach and late change between PF and PNF roles? Surely if in any doubt, disconnect and fly the plane manually and go around if necessary and come in again.

SIA: Good'day Sharon, how are you? We'd like to order a set of main tires and carbon brakes for a 777-300ER please.
Boeing: Hello Tan, fine and you? No problem, I'll have that shipped to you ASAP.SIA: Great Sharon, thank you. Err... could you please add 2 clean﻿ white undies for the cockpit crew as well?
Boeing: Sure Tan, BTW we also have them in brown color so you won't need to order new ones next time.

Joking aside, this must have been a terribly freaking experience for everybody onboard, seeing your plane skidding from left to right, not knowing how it's gonna end. It's not like a car you can (try) countersteer when it skids... I guess when it was clear the crew couldn't TOGA they understood they "just" had to wait the the drama to come to an end.

But it does not! The FDR says nothing TOGA related was going on, CVR however does indicate sounds similar to pressing TOGA. A quote from the report:

Quote:The FDR did not show any indications for the initiation of a go-around procedure. However, the Cockpit Voice Recorder (CVR) recorded at the time of the touch down the PIC's command "ok, flaps 20" together with several sounds which indicate the clicking of the TOGA lever and the movement of the speedbrake handle.

Another interesting part of the report is that the autopilot apparently made the initial bank and turn:

Quote:The airplane began to roll to the left and at 11:09:16 UTC reached a maximum bank angle of 3.5° when it touched down with its left main landing gear. At the time the autopilot was still engaged; the approach mode changed into rollout mode. Because the autopilot generated control inputs to minimise the lateral beam deviation the airplane turned left

Can the experts on this forum tell me why this could potentially be the case? Are there external factors that could lead into this? Could the pilots have caused this? Or is this an autopilot malfunction?

Finally, why is the report focusing on the other aircraft leaving the runway? Is tehre some possibility that it has distracted either the autopilot, the regular pilots, or some navigational aids?

Quoting AirlineCritic (Reply 23):Another interesting part of the report is that the autopilot apparently made the initial bank and turn:

Yes, they were executing an automatic landing : "During the approach briefing the crew had decided to perform an automatic approach and landing".
...and the aircraft was under A/P control.

Quoting AirlineCritic (Reply 23):why is the report focusing on the other aircraft leaving the runway? Is there some possibility that it has distracted either the autopilot, the regular pilots, or some navigational aids?

Any metallic obstacle on or close to the axis of the localiser beamcould warp it, that's why it is important to know whether the AVRO did, in fact disturb the localiser antennas' pattern. Apparently not as it was on the other side of the Loc when the T7 landed.(That's why Cat 2 and 3 protections make sure that holding airplanes are nowhere close to the runway during LVP )

There are a few questions to be asked on this incident :
1/- Where came the Loc signal disturbance from ?
2/- It seems to me that the switch over to the "Roll out" mode from the "Approach" mode was a bit quick : what are the required conditions : only one gear contact doesn't sound right to me.
3/- The DFDR doesn't show any"Go Around" selection, but the Captain said it did and the CVR recorded the call for a reduced flap setting (part of the manoeuvre ). So what in reality did happen ?

Contrail designer

25 rfields5421
: So the locaizer interference was from a departing aircraft, not from an aircraft crossing the CATII/III hold lines? There is at least a 20-30 second

26 PanAm1971
: That is some tough landing gear! Is this possibly a symptom of over reliance on autoland?

27 sandyb123
: Having now read the report in full, I have a few questions... This information is contradictory, the captain with PIC and PF so who was he telling in

28 zkojq
: Its actually quite frightening to see such a large, powerful aircraft skidding down the runway, out of control. According to the BFU report, the co-pi

29 Pihero
: Not quite, the report specifically says : "However, the Cockpit Voice Recorder (CVR) recorded at the time of the touch down the PIC's command "ok, fl

30 flylku
: My initial thought also. I'm sure Boeing never flew the 777 in and out of grass strips during the certification process. Actually, it is the transiti

31 tp1040
: What kind of damage would the plane have.? I would imagine a lot of stress on the landing gear.

32 flightsimer
: It was only 3.5 degrees at the max. At 30ft it was only another 3-4 sec until touchdown. The roll happened so slow and shallow that he probably figur

33 tdscanuck
: This is the normal autopilot response to being right of the localizer beam (presumably because the localizer beam bent to the left). In the air, the

34 Viscount724
: The ground was very firm. Based on photos the wheels barely sunk into the grass.